FEATURE: Add `publish_queue_in_memory` option to distributed cache manager.
FEATURE: Add `publish_queue_in_memory` option to distributed cache manager.

This is a partial revert of e91d41483a89dbcd3a6ecc3aeef47d353b5c6681.
Instead of changing the default behavior of what
`MessageBus::DistributedCache::Manager#publish` should do when it is
called on a Readonly redis, this commit introduces an option to change
the behavior.

SamSaffron/message_bus,SamSaffron/message_bus